1. Technical Field
The present invention relates to a projection display device which performs display utilizing reflection of light from, for example, the windshield that is disposed in front of the driver in a vehicle.
2. Related Art
In, for example, general vehicular head-up display (HUD) devices, an optical path is formed so that an optical image containing various kinds of information to be displayed is projected onto the front windshield or a reflection plate called a combiner from an HUD unit and light reflected from, for example, the front windshield travels toward the eye point of the driver. Therefore, the driver can visually recognize, as a virtual image, an HUD display image appearing on, for example, the front windshield while also visually recognizing a scene ahead of the vehicle through the front windshield. That is, the driver can visually recognize various kinds of information through display on the HUD without the need for moving his or her line of sight while maintaining an ordinary drive state.
For example, Patent documents 1-4 disclose prior art techniques relating to the invention. In the technique disclosed in Patent document 1, to perform pseudo-3D display on the display screen of a game machine, a background region that is adjacent to a display region of a text pattern etc. is shaded.
Patent document 2 discloses a device that, to enable pseudo-3D display, is equipped with a display unit, a mirror for reflecting an image displayed on the display unit toward an observation position, and an angle changing means for changing the angle of the mirror.
Patent document 3 discloses a vehicular display device (HUD device) capable of being installed easily at a proper position in the depth direction.
Patent document 4 relates to an HUD device and discloses a technique for displaying a 3D image by displaying a right-eye virtual image and a left-eye virtual image using a right-eye display and a left-eye display which are independent of each other.